1. Field of the Invention
The present invention relates to a parking aid system for aiding a driver in carrying out reverse parking or parallel parking.
2. Description of the Related Art
A conventional parking aid system is disclosed in Japanese Patent Application Laid-open No. 11-157404 that identifies a parking space according to surrounding obstructions which are detected by, for example, a camera, radar or corner sensor. The parking aid system then calculates a recommended trajectory or locus from the current position of the vehicle to the above-mentioned parking space. The recommended trajectory is displayed over a parking space image on a display unit so as to direct the driver to, for example, steer, brake, accelerate or shift gear, and thus parking is assisted.
However, the above-mentioned conventional parking aid system requires not only various types of sensors such as cameras, radars and comer sensors for identifying a parking space, but also requires a high performance arithmetic unit for calculating the recommended trajectory from the current vehicle position to the parking space and the driving operations required to move the vehicle along the recommended trajectory. Thus, the conventional parking aid system suffers from high costs and the time required for parking is undesirably long due to a long calculation time performed by the arithmetic unit. Furthermore, if the driving operations required to move the vehicle along the recommended trajectory become complicated, the driver cannot instinctively tell whether or not the vehicle can be moved to the parking space by those operations and may feel anxious. Moreover, in using the conventional parking aid system, the driver ends up paying too much attention to the operational instructions and less attention to the surroundings of the vehicle.
Therefore, it is an object of the present invention to provide a parking aid system that overcomes the above-described drawbacks of the conventional parking aid system.
It is also an object of the present invention to provide a parking aid system that can effectively aid a driver in a parking operation by having a simple structural arrangement.
In accordance with a first characteristic of the present invention, the parking aid system includes a display unit to visually display to a driver a target parking position, a subject vehicle position, an expected parking position in the case where the subject vehicle travels with a predetermined steering angle, and an operation switch for selecting a parking aid mode. The display unit displays when the parking aid mode is selected by the operation switch, the target parking position, the subject vehicle position, and the expected parking position, as well as a change in at least one of the subject vehicle position, and the expected parking position, relative to the target parking position according to a change in at least one of the movement of the subject vehicle and the steering angle.
In accordance with the above-mentioned arrangement, when the parking aid mode is selected, the display unit displays not only the target parking position, the subject vehicle position, and the expected parking position, but also a change in the subject vehicle position or the expected parking position relative to the target parking position accompanying the subject vehicle movement or the steering operation. The driver can thus proceed based on the above-mentioned information so that the expected parking position coincides with the target parking position, and confirm on the display unit that the subject vehicle can be moved to the target parking position by the driver""s operation. The driver can thus guide the subject vehicle easily and reliably to the target parking position without feeling anxious. Furthermore, since there is no need for an image processing device for detecting the target parking position or need for calculation of the driver""s operations required for moving the subject vehicle along an expected trajectory, the parking aid system can be realized with very low cost.
Furthermore, in accordance with a second characteristic of the present invention, the display unit also visually displays to the driver an expected trajectory when the subject vehicle travels with a predetermined steering angle as well as a change in the expected trajectory relative to the target parking position according to a change in at least one of the subject vehicle movement and the steering angle.
In accordance with the above-mentioned arrangement, the display unit displays not only the expected trajectory of the subject vehicle, but also a change in the expected trajectory of the subject vehicle relative to the target parking position accompanying movement of the subject vehicle or operation of the steering. The driver can therefore proceed based on the above-mentioned information so that the expected parking position coincides with the target parking position and guide the subject vehicle to the target parking position more accurately.
Furthermore, in accordance with a third characteristic of the present invention, the predetermined steering angle is a maximum steering angle either to the right or the left.
In accordance with the above-mentioned arrangement, since the expected trajectory and the expected parking position when the subject vehicle travels towards the target parking position are determined by estimating the maximum steering angle to the right or the left, the driver can guide the subject vehicle to the target parking position merely by holding the steering wheel at the maximum steering angle position. Thus, the driver""s operation becomes simple, the driver does not feel anxious, and, the driver is able to pay attention to the subject vehicle surroundings.
Furthermore, in accordance with a fourth characteristic of the present invention, the parking aid system further includes first determination means for determining the occurrence of the expected parking position coinciding with the target parking position, a predetermined amount of time that passed in the coincident state, and the time immediately before the coincidence of positions based on a change in at least one of the subject vehicle movement and the steering angle.
In accordance with the above-mentioned arrangement, since the occurrence of any of the events of the expected parking position coinciding with the target parking position, a predetermined amount of time passing in the coincident state, and the time immediately before the coincidence of positions is determined based on a change in the subject vehicle movement or the steering angle, the driver can easily determine whether the subject vehicle can move to the target parking position and thus reliably recognize the timing for starting to reverse the subject vehicle towards the target parking position without feeling anxious.
Furthermore, in accordance with a fifth characteristic of the present invention, the parking aid system further includes notifying means for notifying the driver when the first determination means has determined the occurrence of any of the events of the expected parking position coinciding with the target parking position, a predetermined time having passed in the coincident state, and the time immediately before the coincidence of positions.
In accordance with the above-mentioned arrangement, since the notifying means notifies the driver the occurrence of any of the events of the expected parking position coinciding with the target parking position, a predetermined time having passed in the coincident state, and the time immediately before the coincidence of positions, the driver can easily determine whether or not the subject vehicle can move to the target parking position and thus more reliably recognize the timing for starting to reverse the subject vehicle towards the target parking position without feeling anxious.
Furthermore, in accordance with a sixth characteristic of the present invention, the notifying means notifies the driver using sound.
In accordance with the above-mentioned arrangement, since the notifying means notifies the driver using sound, even when looking away from the display unit, the driver would not fail to notice the determination made by the first determination means, can use the parking aid system appropriately and, can pay sufficient attention to the subject vehicle surroundings.
Furthermore, in accordance with a seventh characteristic of the present invention, the notifying means notifies the driver by changing the displayed form of at least one of the target parking position, the subject vehicle position, the expected trajectory, and the expected parking position displayed on the display unit.
In accordance with the above-mentioned arrangement, since the notifying means notifies the driver by changing the displayed form on the display unit, the driver looking at the display unit can be alerted to reliably recognize the notified content and the parking aid system can thus be used appropriately.
Furthermore, in accordance with an eighth characteristic of the present invention, the displayed form is a color or line.
In accordance with the above-mentioned arrangement, since the displayed form is changed by changing the color or line of the display, the driver can easily recognize the notified content by looking at the color or line of the display.
Furthermore, in accordance with a ninth characteristic of the present invention, the notifying means notifies the driver by displaying, on the display unit, a character string indicating the occurrence of any of the events of the expected parking position coinciding with the target parking position, a predetermined time having passed in the coincident state, and the time immediately before the coincidence of positions.
In accordance with the above-mentioned arrangement, since the notification is carried out by displaying a character string on the display when the expected parking position coincides with the target parking position, a predetermined time has passed in the coincident state, or the time is immediately before the coincidence of positions, the driver can easily and reliably recognize the notified content.
Furthermore, in accordance with a tenth characteristic of the present invention, the parking aid system further includes a back monitor for taking an image of the area behind the subject vehicle, wherein the notifying means notifies the driver by displaying the image taken by the back monitor on the display unit.
In accordance with the above-mentioned arrangement, since the notification is carried out by displaying an image of the area behind the subject vehicle taken by the back monitor on the display unit, the driver can easily and reliably recognize the notified content and comprehend the conditions behind the subject vehicle prior to a subsequent reversing action.
Furthermore, in accordance with an eleventh characteristic of the present invention, the notification by the notifying means is carried out for a predetermined time.
In accordance with the above-mentioned arrangement, since the notification by the notifying means is carried out only for the predetermined time, the driver will not be disturbed while using the parking aid system.
It should be noted here that the above-mentioned predetermined time is set at 1 second in the below described embodiments, but the present invention is not limited thereby.
Furthermore, in accordance with a twelfth characteristic of the present invention, the parking aid system further includes a mark that is used when stopping the subject vehicle so that the target parking position and the subject vehicle position have a predetermined positional relationship when selecting the parking aid mode with the operation switch.
In accordance with the above-mentioned arrangement, since the parking aid system includes a mark that is used when stopping the subject vehicle before starting the parking assistance, the driver can easily stop the subject vehicle so that the target parking position and the subject vehicle position have a predetermined positional relationship. It is therefore possible to prevent the driver from worrying about the predetermined positional relationship being established and repeatedly adjusting the stop position of the subject vehicle due to difficulty in determining whether the predetermined positional relationship has been established.
Furthermore, in accordance with a thirteenth characteristic of the present invention, the parking aid system further includes first cancellation means for canceling the parking aid mode when the difference between the target parking position and the expected parking position exceeds a predetermined value.
In accordance with the above-mentioned arrangement, since the first cancellation means cancels the parking aid mode when the difference between the target parking position and the expected parking position exceeds a predetermined value, it is possible to prevent the parking operation from being started at an inappropriate position, thereby enhancing the reliability of the parking aid system.
It should be noted here that the above-mentioned predetermined value is set at 1 meter in the embodiments, but the present invention is not limited thereby.
Furthermore, in accordance with a fourteenth characteristic of the present invention, the parking aid system further includes second determination means for determining whether the subject vehicle position coincides with a predetermined position on the trajectory to the target parking position that the operational state of the subject vehicle is changed.
In accordance with the above-mentioned arrangement, when the subject vehicle position coincides with a predetermined position on the trajectory to the target parking position that the operational state of the subject vehicle is changed, the second determination means determines that the above-mentioned coincidence of positions has occurred. It is therefore possible to prompt the driver to change the operational state of the subject vehicle at the above-mentioned predetermined position. The driver can thus use the parking aid system appropriately and the reliability of the parking aid system can be enhanced.
Furthermore, in accordance with a fifteenth characteristic of the present invention, the parking aid system further includes notifying means for notifying the driver when the second determination means determines the occurrence of any of the events of the subject vehicle position coinciding with the above-mentioned predetermined position, a predetermined time having passed in the coincident state, and the time immediately before the coincidence of positions.
In accordance with the above-mentioned arrangement, the notifying means notifies the driver when the subject vehicle position has coincided with the predetermined position on the trajectory to the target parking position that the operational state of the subject vehicle is changed, a predetermined time has passed in the coincident state, or the time is immediately before the coincidence of positions. The driver can therefore recognize the timing for changing the operational state of the subject vehicle more reliably and use the parking aid system appropriately without feeling anxious, and the reliability of the parking aid system can be enhanced.
Furthermore, in accordance with a sixteenth characteristic of the present invention, the notifying means notifies the driver using sound.
In accordance with the above-mentioned arrangement, since the notifying means notifies the driver using sound, even when the driver is looking away from the display unit, the driver will not fail to recognize the timing for changing the operational state of the subject vehicle and can use the parking aid system appropriately, the reliability of the parking aid system is enhanced and, the driver is able to pay attention to the subject vehicle surroundings.
Furthermore, in accordance with a seventeenth characteristic of the present invention, the notifying means notifies the driver by changing the displayed form of at least one of the target parking position, the subject vehicle position, the expected trajectory, and the expected parking position displayed on the display unit.
In accordance with the above-mentioned arrangement, since the notifying means notifies the driver by changing the displayed form on the display unit, the driver looking at the display unit is alerted so as to reliably recognize the content of the notification and use the parking aid system appropriately, thereby enhancing the reliability of the parking aid system.
Furthermore, in accordance with an eighteenth characteristic of the present invention, the displayed form is a color or line.
In accordance with the above-mentioned arrangement, since the displayed form is changed by changing the color or line of the display, the driver can easily recognize the notified content by looking at the color or line of the display and use the parking aid system appropriately and, moreover, the reliability of the parking aid system is enhanced.
Furthermore, in accordance with a nineteenth characteristic of the present invention, the notifying means notifies the driver by displaying on the display unit a character string indicating the occurrence of any of the events of the subject vehicle position coinciding with the predetermined position, a predetermined time having passed in the coincident state, and the time immediately before the coincidence of positions.
In accordance with the above-mentioned arrangement, since the notification is carried out by displaying a character string when the subject vehicle position has coincided with a predetermined position, a predetermined time has passed in the coincident state or the time is immediately before the coincidence of positions, the driver can easily and reliably recognize the notified content.
Furthermore, in accordance with a twentieth characteristic of the present invention, the parking aid system further includes a back monitor for taking an image of the area behind the subject vehicle, the notifying means notifying the driver by displaying the image taken by the back monitor on the display unit.
In accordance with the above-mentioned arrangement, since the notification is carried out by displaying an image of the area behind the subject vehicle taken by the back monitor on the display unit, the driver can easily and reliably recognize the notified content and, moreover, the driver can comprehend the conditions behind the subject vehicle prior to a subsequent reversing action.
Furthermore, in accordance with a twenty-first characteristic of the present invention, notification by the notifying means is carried out for a predetermined time.
In accordance with the above-mentioned arrangement, since the notification by the notifying means is carried out merely for the predetermined time, the driver will not be disturbed while using the parking aid system.
It should be noted here that the above-mentioned predetermined time is set at 1 second in the embodiments, but the present invention is not limited thereby.
Furthermore, in accordance with a twenty-second characteristic of the present invention, the display unit displays an expected trajectory according to the predetermined steering angle before the second determination means determines the occurrence of any of the events of the subject vehicle position coinciding with the above-mentioned predetermined position, a predetermined time having passed in the coincident state and the time immediately before the coincidence of positions, and displays an expected trajectory according to the actual steering angle after the determination.
In accordance with the above-mentioned arrangement, since the display unit displays an expected trajectory according to the actual steering angle after the determination by the second determination means, even when the subject vehicle has passed the predetermined position, the driver can adjust the steering angle to make the expected parking position coincide with the target parking position. The driver may therefore stop the subject vehicle at approximately the predetermined position thus improving the ease of use of the parking aid system. It is also possible to prevent use of the parking aid system at an inappropriate position, thereby enhancing the reliability of the parking aid system.
Furthermore, in accordance with a twenty-third characteristic of the present invention, the change in operational state of the subject vehicle is the switch-over between forward and backward travel.
In accordance with the above-mentioned arrangement, even when the subject vehicle has passed the position at which it should have switched over between forward and backward travel during reverse parking, the driver can adjust the steering angle to make the expected parking position coincide with the target parking position. The driver may therefore stop the subject vehicle at approximately the predetermined position, thus improving the ease of use of the parking aid system. It is also possible to prevent use of the parking aid system at an inappropriate position, thereby enhancing the reliability of the parking aid system.
Furthermore, in accordance with a twenty-fourth characteristic of the present invention, the change in operational state of the subject vehicle is a steering operation in an opposite direction.
In accordance with the above-mentioned arrangement, even when the subject vehicle has passed the position at which the steering wheel should have been turned in the opposite direction during parallel parking, the driver can adjust the steering angle to make the expected parking position coincide with the target parking position.
Furthermore, in accordance with a twenty-fifth characteristic of the present invention, the parking aid system further includes third determination means for determining that the subject vehicle position has coincided with the target parking position.
In accordance with the above-mentioned arrangement, since it is determined that the subject vehicle position has coincided with the target parking position, it is possible to prevent the subject vehicle from passing beyond the target parking position and the driver can easily move the subject vehicle to the target position without feeling anxious.
Furthermore, in accordance with a twenty-sixth characteristic of the present invention, the parking aid system further includes a back monitor for taking an image in the direction in which the subject vehicle is being parked, the image taken by the back monitor being displayed on the display unit when the third determination means determines that the subject vehicle position has coincided with the target parking position.
In accordance with the above-mentioned arrangement, when it is determined that the subject vehicle position has coincided with the target parking position, the display unit displays the image of the area behind the subject vehicle taken by the back monitor. The driver can therefore confirm that the parking operation has been proceeding correctly and the reliability of the parking aid system is enhanced.
Furthermore, in accordance with a twenty-seventh characteristic of the present invention, the parking aid system further includes reverse determination means for determining that the subject vehicle is in a reverse mode, the display on the display unit is being changed when the reverse determination means determines that the subject vehicle is in the reverse mode.
In accordance with the above-mentioned arrangement, since the display on the display unit is changed when it is determined that the subject vehicle is in the reverse mode, it is possible to prevent the driver from paying too much attention to the display on the display unit and less attention to the surrounding conditions.
It should be noted here that the reverse switch in the embodiments corresponds to the reverse determination means of the present invention. The reverse determination means detects a state in which the subject vehicle is actually reversing or a state in which the subject vehicle is stopped with reverse range selected.
Furthermore, in accordance with a twenty-eighth characteristic of the present invention, the parking aid system further includes a back monitor for taking an image of the area behind the subject vehicle, the image taken by the back monitor is displayed on the display unit when the reverse determination means determines that the subject vehicle is in the reverse mode.
In accordance with the above-mentioned arrangement, when it is determined that the subject vehicle is in the reverse mode, the image taken by the back monitor is displayed on the display unit. The driver can therefore check the subject vehicle surroundings well, in particular the area behind the subject vehicle, which is the direction of travel. The driver can further confirm that the parking operation is being carried out correctly and the reliability of the parking aid system is enhanced.
Furthermore, in accordance with a twenty-ninth characteristic of the present invention, the parking aid system further includes second cancellation means for canceling the parking aid mode when the speed of travel of the subject vehicle reaches or exceeds a predetermined value.
In accordance with the above-mentioned arrangement, since the parking aid mode is cancelled when the speed of travel of the subject vehicle reaches or exceeds the predetermined value, it is possible to prevent the expected parking position from being displaced from the target parking position due to wheel slip, thereby enhancing the reliability of the parking aid system.
It should be noted here that the above-mentioned predetermined value is set at 10 km/h in the embodiments, but the present invention is not limited thereby.
The above-mentioned objectives, other objectives, characteristics and advantages of the present invention will become apparent from an explanation of preferable embodiments that will be described in detail below by reference to the attached drawings.